* implemented rendering of TRIANGLE_STRIP and TRIANGLE_FAN primitives (I'm not sure if I'll leave the kernel code like that, but it doesn't seem to affect the frame rate, probably due to all work-items taking the same branch)
 * moved camera_setup buffer update to an extra function, so it can be called externally when not using the provided camera functionality (the draw_state camera_setup must of course still be in a valid state!)
 * extended the oclr_rtt sample a little bit to test the rendering of TRIANGLE_STRIP and TRIANGLE_FAN primitives (compile-time switch to either render a rectangle, a hexagon or a flag)
 * removed now obsolete opengl rtt class